Production of vinyl aryl ethers



Patented Nov. 30, 1954 2,695,920 IRODUCTION OF VINYL ARYL ETHERS Joseph M. Willdnson, Eastern, and Edgar S. Miller, Bethlehem, Pa., assignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application January 4, 1952, Serial No. 265,044

6 Claims. (Cl. 260-612) This invention relates to vinyl aryl ethers and particularly to an improved process of preparing the same.

Vinyl aryl ethers have been prepared by several methods. For instance, vinyl phenyl ether has been prepared by heating fi-bromoethyl phenyl ether with twice its weight of powdered potassium hydroxide. Temperatures as high as 290 C. were required and yields were less than 50% of the theoretical. Obviously, this method as serious limitations from the industrial standpoint. Vinyl phenyl ether, the three vinyl tolyl ethers, and vinyl l-naphthyl ether have been prepared by a vinylation process, i. e., by the action of acetylene on phenol, the cresols, and l-naphthol, respectively. These prepara tions have been described by M. F. Shostakoyskii and M. S. Burmistrova, in the Journal of Applied Chemistry (USSR), 15, 260-266 (1942). These authors used potassium hydroxide as a catalyst and the amount corresponded to 20% of the weight of phenol or cresol. However, they reported that resinification occurred during vinylation unless water was added. They recommended 1015% of the weight of phenol or cresol as water.

sodium phenolate and potassium hydroxide as catalysts and methanol as a solvent. Treatment with a 2:1 mix ture of acetylene and nitrogen for 2024 hours at 180 C.

amount of phenol as an impurity which must be removed by treatment with caustic soda. Moreover, Reppes process is limited to phenolic compounds free of exchangeable halogen groups which might react with the alkali in an undesired manner.

To provide an improved process of preparing vinyl aryl ethers which overcomes the shortcomings of the Reppe method constitutes the object of the present invention.

We have found that in the vinylation of phenolic compounds the nitrogen in the acetylene mixture can be replaced by propane in the same percentage ratio and that such mixture eliminates the hazards of detonation. No

ably a small amount of water is present, being formed from the reaction of alkali metal hydroxide and phenol.

We have further found that a total pressure of not more than atmospheres gives satisfactory yields and substantial economies of operation result because the equipment need be designed for only A to /3 of the pressures required by former processes. In addition, the

of reaction is rapid even at lower pressures and the rate time require for carrying out the re metal hydroxide is employed.

Another significant and unexpected aspect of our improved process is that chlorinated mon The autoclave is sealed, pressure teste dry nitrogen followed with propane.

d, and purged with The autoclave is then sealed and heated to a temperature ranging between 175-190" C., preferably to 185 pane is then introduced to a press h agitation. Propheres) phenol 4-methylphenol Z-methoxyphenol 0-, m-, and p-Cresol 1,2-dirnethyl-3-hydroxybenzene l,2-dimethyl-4-hydroxybenzene l ,3-dimethyl-2-hydroxybenzene l,3-dimethyl-4-hydroxybenzene l 3-dimethyl-5-hydroxybenzene l,4-dimethyI-Z-hydroxybenzene Thymol Carvacrol ot-Naphthol B-Naphthol 1,3-naphthol o-Chlorophenol p-Chlorophenol 3-hydroxybenzanthrone 4-hydroxybenzanthrone 3-hydroxybenzophenone S-hydroxydiphenyl 4-hydroxydiphenyl 3-hydroxyfluorenone 4-hydroxyfluorenone 6-hydroxy-3-methyl coumarine 4-hydroxyfluoranthrene 3-hydroxy-1,Z-benzanthrene Bz-S-hydroxybenzanthrone Hydroquinone-monomethyl ether 4-hydroxy-4-methyldiphenyl 4'-hydroxydiphenyl Hydroxyphenylene l -hydroxyphenanthrene Z-hydroxyphenanthrene 3-hydroxyphenanthrene 4-hydroxyphenanthrene 9-hydroxyphenanthrene p-Hydroxyphenyl benzyl ether 4-hydroxy stilbene 3-hydroxy chrysene 4=hydroxy chrysene' S-hydroxy chrysene l-hydroxy perylene 2,3-dichlorophenol 2,4dichlorophenol 2,5-dichlorophenol 2,6-dichlorophenol 3,4-dichlorophenol 3,5-dichlor'ophenol Eugenol Guaiacol Veratrol 2-methoxy-4-methylphenol p-Hydroxybiphenyl p-Tert.-amylphenol p-( 1,1,3 ,3-tetramethylbutyl) -phenol l-hydroxyanthracene 2-hydroxyanthracene 9-hydroxyanthracene 9-phenanthrol 2-hydroxyfiuorene 5-hydroxy-l ,2,3 ,4-tetrahydronaphthalene 6-hydroxy-1,2,3 ,4-tetrahydronaphthalene The alkali metal hydroxides which may be employed are lithium hydroxide, potassium hydroxide, sodium hydroxide, and the like. For practical purposes, we prefer to employ potassium hydroxide because of the greater solubility of the potassium salt of the phenol in excess phenol.

Our improved process will be'more' fully described in conjunction with the'following examples. It is to be understood, however, that the examples are given by way of illustration and the invention is not to be'limited by the-details set forth therein.

EXAMPLE I Vinyl phenyl ether Astainless steel, l-liter autoclave was charged with 376 grams (4 mols) of phenol and 112.8 grams (2.01 mols, 30 per cent by weight of phenol) of potassium hydroxide. The autoclave was sealed, pressure-tested for leaks, and purged 3 times with dry nitrogen and twice with propane. The autoclave was then sealed and heated to 185 C. with agitation. Propane was then introduced to a pressure of 70 p. s. i. g. (pounds/square inch-gauge pressure). Acetylene was added to 200 p. s. i. g., and the reaction was allowed to run for 10 hours at 185 C. The autoclave was allowed to cool and the gases vented. The product was discharged and subjected to steam distillation. The organic layer was separated from the distillate and dried over anhydrous sodium sulfate. Distillation of the product at atmospheric pressure over 2 grams of sodium carbonate gave 318 grams or 67% of theory of vinyl phenyl ether of the following properties: boiling point 154-1555 C., n 1.519; and D4 0.97 gram per ml.

The carbon and hydrogen analyses showed the following results:

C calculated- 79.97% H calculated 6.71% C found 79.92% H found 6.78%

The vinyl ether content was 99.8% and free phenol was 0.0%.

While utilizing the same equipment, technique, and conditions described in Example I, but using a potassium hydroxide concentration of by weight of phenol present, the yield was only approximately Under the same conditions, but using a potassium hydroxide concentration of 20% by weight of phenol present, the yield was only 30%. For a concentration of 10% by weight of phenol present, only traces of the desired product are obtained. A catalyst concentration of 3% which, in most cases, works very well in the vinylation of alcohols, gave no indication of any reaction when applied to phenol and phenolic compounds.

EXAMPLE II Vinyl p-chlorophenyl ether to the vinylation reaction. Processing of the reaction mixture yielded 244 grams of the ether with the following properties: boiling point andD4 1.135;

C./20 mm.; n 1.538;

EXAMPLE III Vinyl-2,4-dichlorophenyl ether Using the equipment, conditions and techniques described in Example I, 326 grams (2 mols) of 2,4-dichlorophenol and 97.8 grams (1.7 mols or 30% by weight of phenol present) of potassium hydroxide were submitted to the conditions of vinylation. tion mixture yielded theether having the following physical properties: boiling point l07 C./l4 mm.; n 1.555; and D4 1.276.

EXAMPLE IV C calculated 81.72 H calculated 9.15

C found 81.65 H found 9.12 By replacingxthephenol with other phenols and utilizing the same-reaction conditions as in Example I, the following vinyl and-aryl ethers'may be prepared.

Name Formula M01. W. Boiling Point Vinyl o-tolyl ether CnHmO 134.17 169 0 Vinyl m-tolyl other. 011E100 134.17 0

Vinyl p-tolyl ether. OQHioO 134.17 177 C Vinfi l 2-methoxypheny1 CqHitiO: 150.17 202 C ct er.

Vinyl l-naphthyl ether... 01211100 170. 20 258 C.

Vinyl Z-naphthyl ether.. CuHwO 170. 20 264 0.

Vinyl 2-isopropyl-5-methyl 01211150 176. 25 100 C./l4 mm.

phenyl ether.

Vinyl 5-isopropyl-2-methyl CrzHmO 176. 25 218 C.

phenyl'ethcr.

Viral 2,4-dichlorophcnyl 081100120 189.03 104 C./14 mm.

While we have disclosed the ourinvention and the preferred modes of carrying the same into effect, it will be readily apparent to those skilled in this art that'many variations'may be made therein without departing from 'the spirit thereof. Accordingly, the scope of our invention is to belimited solely by the following claims.-

We claim:

1. In the process of preparing vinyl aryl ethers characterized by the following general formula:

wherein R represents the residual nuclear radical of a monohydric phenol, the improvement which consists of heating an alkali stable monohydric phenol with 25-30% by weight of the phenol of potassium hydroxide in the .presence of a mixture of acetylene and propane at a temperature ranging between 17519'0 C. and at a pressure of not more than 15 atmospheres.

2. In the process of'preparing vinyl phenyl ether, the improvement whichv consists of heating two molecular ...equivalents of alkali stable phenol and one molecular equivalent of potassium hydroxide in the presence-of a mixture. of acetylene and propane at a temperature of C. and a pressure of approximately 14 atmospheres.

3. In the process of. preparing vinyl p-chlorophenyl ether, the improvement which consists of heating one molecular equivalent of alkali stable p-chlorophenol and 0.66 molecular equivalent of potassium hydroxide in the presence of-a mixture of acetylene and propane at a temperature of 185 C. and a pressure of approximately 14 atmospheres.

4. In the process of preparing vinyl-2,4-dichlorophenyl ether, the improvement which consists of heating two molecular equivalents-of alkali stable 2,4-dichlorophenol and 1.7 molecular equivalents of potassium hydroxide in the presence of a mixture of acetylene and propane at a and a-pressure of approximately 14 atmospheres.

Processing of the reacpreferred embodiments of 5. In the process of preparing vinyl p-terL-butylphenyl ether, the improvement which consists of heating one molecular equivalent of alkali stable p-tert.-butylphenol and 0.8 molecular equivalent of potassium hydroxide in the presence of a mixture of acetylene and propane at a temperature of 185 C. and a pressure of approximately 14 atmospheres.

6. In the process of preparing vinyl l-naphthyl ether, the improvement which consists of heating one molecular equivalent of alkali stable a-naphthol and 0.77 molecular equivalent of potassium hydroxide in thepresence of a mixture of acetylene and propane at a temperature of 175 C. and a pressure of approximately 14 atmospheres.

Number 5 1,959,927 2,066,076 2,354,632

10 Number UNITED STATES PATENTS Name Date Reppe May 22, 1934 Reppe et al Dec. 29, 1936 Wolfram et al July 25, 1944 FOREIGN PATENTS Country Date Great Britain June 21, 1935 Great Britain Aug. 29, 1951 

1. IN THE PROCESS OF PREPARING VINYL ARYL ETHERS CHARACTERIZED BY THE FOLLOWING GENERAL FORMULA: 